dsa: mv88e6xxx: Use bus in mv88e6xxx_lookup_name()

mv88e6xxx_lookup_name() returns the model name of a switch at a given
address on an MII bus. Using mii_bus to identify the bus rather than
the host device is more logical, so change the parameter.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx.c

@@ -3068,11 +3068,10 @@ int mv88e6xxx_get_temp_alarm(struct dsa_switch *ds, bool *alarm)
 }
 #endif /* CONFIG_NET_DSA_HWMON */
 
-static char *mv88e6xxx_lookup_name(struct device *host_dev, int sw_addr,
+static char *mv88e6xxx_lookup_name(struct mii_bus *bus, int sw_addr,
 				   const struct mv88e6xxx_switch_id *table,
 				   unsigned int num)
 {
-	struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
 	int i, ret;
 
 	if (!bus)
@@ -3090,7 +3089,8 @@ static char *mv88e6xxx_lookup_name(struct device *host_dev, int sw_addr,
 	/* Look up only the product number */
 	for (i = 0; i < num; ++i) {
 		if (table[i].id == (ret & PORT_SWITCH_ID_PROD_NUM_MASK)) {
-			dev_warn(host_dev, "unknown revision %d, using base switch 0x%x\n",
+			dev_warn(&bus->dev,
+				 "unknown revision %d, using base switch 0x%x\n",
 				 ret & PORT_SWITCH_ID_REV_MASK,
 				 ret & PORT_SWITCH_ID_PROD_NUM_MASK);
 			return table[i].name;
@@ -3106,9 +3106,13 @@ char *mv88e6xxx_drv_probe(struct device *dsa_dev, struct device *host_dev,
 			  unsigned int num)
 {
 	struct mv88e6xxx_priv_state *ps;
+	struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
 	char *name;
 
-	name = mv88e6xxx_lookup_name(host_dev, sw_addr, table, num);
+	if (!bus)
+		return NULL;
+
+	name = mv88e6xxx_lookup_name(bus, sw_addr, table, num);
 	if (name) {
 		ps = devm_kzalloc(dsa_dev, sizeof(*ps), GFP_KERNEL);
 		if (!ps)